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9.2 Calibration Accuracies per Detector

The calibration accuracy consists of the following items:
Absolute accuracy: is a measure of the uncertainty of the flux with respect to an independently and absolutely calibrated flux standard.
Relative (multi-filter) accuracy: is a measure of the uncertainty of a spectral energy distribution derived from an ISOPHOT multi-filter observation. For PHT-S this is a measure of the uncertainty of the spectral shape between different wavelength ranges of groups of about 20 consecutive pixels.
Relative flux reproducibility: is a measure of the flux consistency between repeated observations of a non-variable source.

An overview of the calibration accuracies per detector in the light of the accuracy definitions given above is presented in Table9.1.

Table 9.1: ISOPHOT photometric calibration accuracy overview.
detector source source typical absolute reproducibility multi-filter
  type brightness on-source accuracy 1$\sigma$ of accuracy
  point/   integration   20 samples  
  extended   [s] [%] [%] [%]
P1 p, star 50 - 6000 Jy 32 $<$10 5 $<$20
P1 p, star 0.1 - 50 Jy $\le$256 40 10 -
P1 p, chop 0.06 - 10 Jy 128 $<$25 $<$16 $<$25
P2 p, star 10 - 200 Jy 32 $<$10 2 5
P2 p, star 0.5 - 10 Jy $\le$256 $<$15 12 -
P2 p, chop 0.2 - 20 Jy 128 $<$30 $<$10 -
P3 p, star 0.5 - 25 Jy 32 10 7 $<$10
P3 p, star $<$0.5 Jy $\le$256 20 7 -
P3 p, chop $\ge$0.8 Jy$^{**}$ 128 $<$25 $<$15 $<$25
C100 p, star 0.5 - 25 Jy 32 15 $\ge$3 $<$25
C100 p, star 0.05 - 0.5 Jy $\le$256 $<$25$^*$ 20 -
C100 e, star 5 - 15 MJysr$^{-1}$ 32 25 10 20
C100 p, chop $\ge$0.2 Jy$^{**}$ 128 $<$30 $<$15 $<$20
C200 p, star 1 - 900 Jy 128 10 10 20
C200 p, star 0.2 - 1 Jy $\le$256 $<$20$^*$ 10 -
C200 e, star 4 - 10 MJysr$^{-1}$ 64 20 10 20
C200 p, chop $\ge$1.5 Jy$^{**}$ 128 $<$40 - -
SS p, star 1 - 6000 Jy 256 $<$10 - $<$15
SS p, chop 0.5 - 500 Jy 1024 $<$10 - $<$10
SS e, star 30 - 3000 MJysr$^{-1}$ 256 $<$10 - $<$15
SL p, star 0.3 - 1500 Jy 256 $<$10 - $<$15
SL p, chop 0.2 - 200 Jy 1024 $<$10 - $<$10
SL e, star 5 - 10000 MJysr$^{-1}$ 256 $<$10 - $<$15 

   Notes 		 

  $^{*}$ for mini-map photometry using PCAS products 

  $^{**}$ for fainter fluxes careful estimate of cirrus confusion necessary

next up previous contents index
Next: 9.3 Status of Scientific Up: 9. Photometric Calibration Accuracies Previous: 9.1 Overview
ISO Handbook Volume IV (PHT), Version 2.0.1, SAI/1999-069/Dc